Nowadays, a power-driving motor is generally implemented with a hub motor or an axis motor. The hub motor is as disclosed in U.S. Pat. Nos. 7,156,196 and 9,453,536. The hub motor is a flat-type motor large in diameter and small in width and is mainly fitted to a wheel to directly drive the wheel. Further, the axis motor is as disclosed in US patent No. 2016/0303961. The axis motor is mainly fitted to an axis position of a frame of the bike. When being implemented, the axis motor is needed to work with a gear box. However, practically, the hub motor and the axis motor are easily damaged and affect the appearance of power-driving bike, thereby lowering the whole design of the power-driving bike.
Nowadays, there are also some types of power-driving bikes, such as an assistant power-driving bike (Pedal-Assist Electric Bike), which includes a power-driving motor installed in a seat tube or down tube for keeping the design of the whole appearance of bike. However, the seat tube and down tube of the frame of the bike are not big in diameter, so the power-driving motor must be designed for its diameter complying with the diameter of the seat tube or down tube; namely, only the power-driving motor of small diameter may be implemented. Accordingly, the power-driving motor of equivalent length if being reduced in size affects the whole torque output of the power-driving motor and thus cannot supply enough power to the power-driving bike. Besides, although the length of the power-driving motor may be added, if the whole structure of power-driving motor is expanded in length, the weight and design cost of the power-driving motor are added, the design becomes difficult, and the operation efficiency is lowered, thereby the problems being not solved.
Consequently, because of the technical defects described above, to provide the rotary valve improver, the applicant, based on many years of research and experience in the relevant industry, has developed the present invention, which may effectively improve the defects described above.